OP,
I don't have a problem with "outside dogs" as long as their needs are being met,
Dobermans are very intelligent dogs, they need a purpose, they need constant excise,
our working doberman are training for at least four hours a day,
they are a dog that benefits from close handler work, and interaction,
the breed was created by a german bailiff tax collector, he wanted a dog that would focus on human behaviour and enter personal space, not as natural behaviour for standard K9,
I don't think this breed does do well as an outside dog, they need one to one, and a huge commitment to training,
the actions she is taking with your son is not acceptable, and really dangerous, that must not happen again, she must not ever put her mouth on a human, that should of been installed in her training before 12 weeks,
If you want to keep her, someone needs to get up at 6am tomorrow, walk for an hour and half, after the first hour do some training, repeat, three or four times a day,
dog agility, sniffer training, rescue training, that dog has an amazing level of intelligent, it needs occupying.
make sure all family members are on board and agree calls, signals,
if you are shouting or getting stressed, you are not doing correctly,
your dogs should be fed in calmest order, dog sitting quietest gets it bowl put down first,
find a decent trainer, enrol on a program,
Potentially you have an amazing dog there, or potentially you have a very nasty future.
What ever you do, you must never ever put the child or the dog in a space together, until the dog has been trained, the dog at the moment will end up hurting the child, not fair to either dog or child.
A doberman is always looking for a job vacancy, if you do not keep it occupied it will write it own's job description.
We get ours from Russia to avoid the heart problems as the gene pool was dived by the iron curtain, which is one good thing that came out of the cold war, or the breed would of been well and truly stuffed.